body {
  margin: 0;
}
* {
  box-sizing: border-box;
}
.calculator {
  display: grid;
  grid-template-columns: repeat(4,6rem);
  grid-template-rows: minmax(6rem,auto) repeat(5,4rem);
  gap: 1px;
  background-color: rgba(191, 191, 191, 0.3);
  width: calc(24rem + 5px);
  margin: 0 auto;
  border: 1px solid black;
}
.output {
  grid-column: 1/span 4;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  justify-content: space-around;
  padding: 10px;
  word-wrap: break-word;
  word-break: break-all;
  border: 1px solid black;
}
.last-output {
  font-size: 1rem;
}
.current-output {
  font-size: 3rem;
}
.button-ac {
  grid-column: 1/span 2;
}
.button-equal {
  grid-column: 3/span 2;
}
.calculator > button {
  background-color: white;
}
.calculator > button:hover {
  background-color: #b5b5b5;
}